Background Breast cancer has become the leading cause of global cancer incidence. With the improvement of treatment methods, financial toxicity among breast cancer patients has been widely studied. Objectives The aims of this study were to summarize the risk factors for and outcomes of financial toxicity among breast cancer patients, to identify populations at risk for financial toxicity, to identify the consequent health impacts, and to provide evidence for subsequent intervention programs. Methods We searched the PubMed/MEDLINE, Web of Science, MEDLINE (Ovid), CINAHL (EBSCO), EMBASE (Ovid), ProQuest, and China National Knowledge Infrastructure databases from inception to July 21, 2022. We followed the updated framework for scoping reviews proposed by the Joanna Briggs Institute. Results A total of 31 studies were included. Risk factors and outcomes of financial toxicity among breast cancer patients were identified and extracted. The risk factors included socioeconomic, demographic, disease and treatment, and psychological and cognitive factors, whereas financial toxicity affected the physical, behavioral, and psychological domains of breast cancer patients, resulting in material loss, coping behaviors, and impaired health-related quality of life. Conclusion Financial toxicity among breast cancer patients depends on multiple factors and has profound effects. The findings will be helpful for identifying breast cancer patients at a high risk of financial toxicity and developing intervention programs to reduce financial toxicity and outcomes. Implications for Practice More high-quality prospective, multicenter studies should be conducted in the future to better understand the trajectory of and risk factors for financial toxicity. Further studies should merge symptom management and psychosocial support into intervention programs.